Agrobacterium-mediated gene transfer is widely used for the production of transgenic dicots. However, monocotyledonous plants (monocots) are generally less susceptible than dicots to Agrobacterium-mediated transformation, and thus direct DNA transfer methods such as electroporation and particle gun transformation have been more widely used. Moreover, direct DNA transfer methods suffer deficiencies, including frequent incorporation of the DNA into the host genome as multiple copies of the desired gene are rearranged together with flanking sequences from the plasmid vector. These rearrangement and integration events may result in gene expression that is aberrant and unstable in R0 and progeny plants.
Agrobacterium-mediated gene transfer usually results in the insertion of a discrete, unrearranged DNA segment into the host genome, and thus better methods for the Agrobacterium-mediated transformation of monocots are needed.